CN101842645B

CN101842645B - Refrigeration cycle device

Info

Publication number: CN101842645B
Application number: CN2008801141141A
Authority: CN
Inventors: 冈崎多佳志; 亩崎史武; 大林诚善
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2007-11-30
Filing date: 2008-11-20
Publication date: 2012-11-28
Anticipated expiration: 2028-11-20
Also published as: EP2647928A3; EP2647926A3; ES2650233T3; DK2647925T3; EP2647927A2; DK2647927T3; EP2196745A4; ES2605462T3; EP2647927B1; EP2647928B1; CN101842645A; EP2196745B1; DK2647926T3; EP2647925A3; WO2009069524A1; JP2009133547A; EP2647927A3; CN102425872B; EP2647925A2; ES2700938T3

Abstract

A refrigeration cycle device having a compressor (1), a heat radiator (2), a pressure reduction means (3), a heat absorber (4), and an internal heat exchanger (5) for exchanging heat between refrigerant on the exit side of the heat radiator and refrigerant on the exit side of the heat absorber. The refrigeration cycle device further comprises a first temperature detection means (30) for detecting the temperature of refrigerant between the exit of the compressor (1) and the entrance of the heat radiator (2), and also comprises a second temperature detection means (31) for detecting the temperature of refrigerant between the exit of the heat radiator (2) and the entrance on the high-pressure side of the internal heat exchanger (5). The degree of opening of the pressure reduction means (3) is controlled so that the difference (DeltaT) between the temperature detected by the first temperature detection means (30) and the temperature detected by the second temperature detection means (31) is a target value.

Description

Freezing cycle device

Technical field

The present invention relates to use the freezing cycle device of inner heat exchanger, particularly relate to the cold-producing medium control that is used for stably guaranteeing performance.

Background technology

Below, existing example is described.

In the past; As the hot-water supply that freezing cycle device is housed; For example proposing (for example has such hot-water supply; With reference to patent documentation 1), " this hot-water supply has cold-producing medium circulation and the circulation of heat supply water, and this cold-producing medium circulation is used heat exchanger, electric expansion valve to reach gas in addition by compressor, heat supply water to constitute as the heat source side heat exchanger of thermal source; This heat supply water circulation is made up of with heat exchanger and heat supply water tank supply-water pump, heat supply water; Wherein: the compressor that uses the ability variable type; Simultaneously; Set up the ability control module that carries out the ability control of compressor corresponding to the variation of the external environment condition of heat source side heat exchanger, in addition, set up expansion valve opening control module and rotary speed controling unit; This expansion valve opening control module is corresponding to the variation of the external environment condition (for example, outer temperature degree) of heat source side heat exchanger, so that the discharge temperature of compressor becomes the aperture control that the mode of desired value is carried out electric expansion valve; This rotary speed controling unit is controlled so that the rotating speed of compressor becomes the mode of desired value corresponding to the variation of the external environment condition of heat source side heat exchanger; Because (for example corresponding to the external environment condition of heat source side heat exchanger; Outer temperature degree) variation is so that the discharge temperature of compressor becomes the aperture that the mode of desired value is controlled electric expansion valve; Simultaneously, corresponding to the variation of the external environment condition of heat source side heat exchanger so that the rotating speed of compressor becomes the mode of desired value controls, so; Can obtain the more best running state of coupling of heat supply outlet capacity and heat supply water load; Coefficient of refrigerating performance (COP) can be improved, simultaneously, the miniaturization of components of heat exchanger etc. can be made ... "

In addition; Proposition (for example has such hot water supply device; With reference to patent documentation 2); " this hot water supply device uses the overcritical heat pump cycle heating heat supply water of on high-tension side refrigerant pressure more than the cold-producing medium critical pressure to use fluid, it is characterized in that: have compressor, radiator, pressure reducer, evaporimeter; This radiator makes the cold-producing medium and the heat supply water of discharging from compressor carry out heat exchange with fluid, and so that flow of refrigerant and heat supply water with fluid flowing phase to mode constitute; This pressure reducer reduces pressure to the cold-producing medium that flows out from radiator; This evaporimeter makes the cold-producing medium evaporation of flowing out from pressure reducer, makes cold-producing medium absorb heat, and cold-producing medium is flowed out towards the suction side of compressor; So that the cold-producing medium that flows out from radiator is controlled on high-tension side refrigerant pressure with the mode that flow into the temperature difference (Δ T) of the heat supply water of radiator with fluid and become the regulation temperature difference (Δ To) ".In this prior art example, can improve the heat exchanger effectiveness of radiator, the efficient of raising heat pump.

Patent documentation 1: No. 3601369 communique of Japan Patent (the 6th page, Fig. 1)

Patent documentation 2: No. 3227651 communique of Japan Patent (the 1-3 page or leaf, Fig. 2)

Summary of the invention

In 2 prior art examples shown in above-mentioned; All be so that the discharge temperature of compressor or the cold-producing medium that flows out from radiator are controlled refrigerant condition with the mode that flow into the temperature difference (Δ T) of the heat supply water of radiator with fluid and become desired value; The running that implementation efficiency is good, but have such problem, promptly; The efficient (COP) of freeze cycle become maximum near; In the control based on the outlet side (above-mentioned temperature difference T) of the entrance side (above-mentioned discharge temperature) of radiator or radiator only, the variation of discharge temperature or temperature difference T is little, is difficult to stably be controlled to be the good operating condition of efficient.In addition, also there is such problem, that is, do not consider in refrigerant loop, to exist the action of the occasion of inner heat exchanger, so, be difficult to stably be controlled to be the good operating condition of efficient.

The present invention makes for the prior art problems that solves above-mentioned that kind; Its purpose is to obtain such freezing cycle device; This freezing cycle device will be controlled to be desired value based on the normal condition of radiator and the operation values of radiator outlet state, thus the good operating condition of implementation efficiency stably.

In order to solve the problem of above-mentioned that kind; Freezing cycle device of the present invention comprises decompressing unit, heat dump, the inner heat exchanger that compressor, radiator, aperture can change at least, and this inner heat exchanger makes the cold-producing medium of radiator outlet portion and the cold-producing medium of heat dump export department carry out heat exchange; It is characterized in that: have the first refrigerant condition detecting unit of the normal condition that detects radiator at least and detect, so that the mode that becomes desired value according to the operation values of the output computing of the output of the first refrigerant condition detecting unit and the second refrigerant condition detecting unit is controlled the aperture of decompressing unit from the second refrigerant condition detecting unit of the refrigerant condition between the high-pressure side inlet that exports to inner heat exchanger of radiator.

The effect of invention

In the present invention, according to the refrigerant condition of the normal condition of radiator and radiator outlet portion so that the maximum mode of COP is controlled expansion valve opening, so, can obtain stably to realize the freezing cycle device of high efficiency running.

Description of drawings

Fig. 1 is the figure of the formation of the freezing cycle device of expression embodiment of the present invention 1.

Fig. 2 is the figure of the action of the running on the P-h line chart of expression embodiment of the present invention 1.

Fig. 3 is the figure of the Temperature Distribution of cold-producing medium in the water heat exchanger of expression embodiment of the present invention 1 and water.

Fig. 4 is the figure of the recurrent state for expansion valve opening of expression embodiment of the present invention 1.

Fig. 5 is the figure of the variation of each operation values for expansion valve opening, the heating efficiency of expression embodiment of the present invention 1, COP.

Fig. 6 is the figure of the variation of another each operation values for expansion valve opening, the heating efficiency of expression embodiment of the present invention 1, COP.

Fig. 7 is the figure of the control flow chart of expression embodiment of the present invention 1.

Fig. 8 is the figure of the formation of the freezing cycle device of expression embodiment of the present invention 2.

Fig. 9 is the figure of the action of the running on the P-h line chart of expression embodiment of the present invention 2.

The explanation of symbol

1 compressor, 2 radiators (water heat exchanger), 3 expansion valves, 4 heat dumps (evaporimeter); 5 inner heat exchangers, 20 supply the hot water side pump, 21 hot water reservoir, 22 utilize the side pump; 23,24,25 open and close valves, 29 pressure fans, 30,31,32,33,41,42,52 temperature detecting units, 35,51 pressure sensing cells; 40 control device, 50 heat power supply devices, 60 hot water storage devices

The specific embodiment

Embodiment 1

Below, the freezing cycle device of embodiment of the present invention 1 is described.

Fig. 1 is the structure chart of the freezing cycle device of expression embodiment of the present invention.In the drawings, the freezing cycle device of this embodiment for use carbon dioxide (below use CO ₂Expression), constitutes by heat power supply device 50, hot water storage device 60, control device 40 that they are controlled as the hot water supply device of cold-producing medium.In this embodiment,, also can be air conditioner though the example of expression hot water supply device is not limited thereto.Equally, cold-producing medium is not limited to carbon dioxide, also can be the HFC series coolant.

Heat power supply device 50 is made up of compressor 1, radiator (below be called " water heat exchanger ") 2, inner heat exchanger 5, decompressor 3 (below be called " expansion valve "), heat dump 4 (below be called " evaporimeter "), inner heat exchanger 5; 1 pair of cold-producing medium of this compressor compresses; This radiator 2 will receive the high-temperature high-pressure refrigerant of compression in compressor 1 heat takes out; 5 pairs of this inner heat exchangers further cool off from the cold-producing medium that water heat exchanger 2 has come out; 3 pairs of cold-producing mediums of this decompressor reduce pressure, and can change aperture; This heat dump 4 makes the cold-producing medium evaporation that in expansion valve 3, has been depressurized; This inner heat exchanger 5 further heats the cold-producing medium that comes out from evaporimeter 4.That is inner heat exchanger 5 heat exchanger that carries out heat exchange for the cold-producing medium of the export department of the cold-producing medium of the export department that makes water heat exchanger 2 and evaporimeter 4.Has the pressure fan 29 of air being delivered to the outer surface of evaporimeter 4.In addition, have the discharge temperature that detects compressor 1 first temperature detecting unit 30, detect the outlet temperature of water heat exchanger 2 second temperature detecting unit 31, detect the inlet refrigerant temperature of evaporimeter 4 the 5th temperature detecting unit 32, detect the 6th temperature detecting unit 33 of the inlet temperature of compressor 1.And, above-mentioned first temperature detecting unit 30 and second temperature detecting unit 31, after be equivalent to the first refrigerant condition detecting unit of the present invention and the second refrigerant condition detecting unit respectively in the control example of Fig. 7 of stating.

Hot water storage device 60 is connected on the water heat exchanger 2 as radiator through pipe arrangement, by heat source side pump 20, hot water reservoir 21, utilize side pump 22, open and

close valve

23,24,25 to constitute.Here, open and

close valve

23,24,25 can be the simple valve that only carries out opening and closing operations, also can be the valve that can change aperture.In the occasion that the water level of hot water reservoir 21 has descended, open and close valve 24,25 is closed, and opens open and close valve 23, carry out water supply is heated to the hot water storage running of set point of temperature.In addition, the occasion that wait in the winter time that radiation loss is big, temperature in the hot water reservoir 21 has descended, open and

close valve

23,25 is closed, and the circular heating running that once more low-temperature water heatings in the hot water reservoir 21 boiled is opened, carried out to open and close valve 24.In addition, when utilize supplying with hot water, open and close valve 23,24 is closed, and open and close valve 25 is opened, utilize 22 actions of side pump, with the delivery that has stored to utilizing side.And; The 3rd temperature detecting unit 41 of the inlet temperature that detects heated medium (water) is installed at the entrance side of water heat exchanger 2; The 4th temperature detecting unit 42 of the outlet temperature that detects heated medium (water) is installed at the outlet side of water heat exchanger 2 in addition.

Control device 40 uses the detected value from first temperature detecting unit 30, second temperature detecting unit 31, the 5th temperature detecting unit 32, the 6th temperature detecting unit 33, the 3rd temperature detecting unit 41 and the 4th temperature detecting unit 42 to carry out computing, controls the aperture of expansion valve 3, the rotating speed of compressor 1 and the rotating speed of heat source side pump 20 respectively according to this operation values.

Fig. 2 is the P-h line chart of the recurrent state in the hot water storage running of explanation freezing cycle device shown in Figure 1.In Fig. 2, solid line is represented the refrigerant condition under a certain expansion valve opening, and A, B, C, D, E, F represent the refrigerant condition in the hot water storage running.When carrying out the hot water storage running, the high-temperature high-pressure refrigerant (A) of discharging from compressor 1 flow into water heat exchanger 2.In water heat exchanger 2, cold-producing medium, heats up thereby make to supply water Yi Bian reduce the temperature of self on one side to the water-cooled that in the hot water storage loop, circulates.The cold-producing medium (B) that has flowed out from water heat exchanger 2 dispels the heat inner heat exchanger 5, and temperature further reduces (C), by expansion valve 3 decompressions (D), becomes low-temperature low-pressure refrigerant.From the air caloric receptivity, self evaporates (E) to low-temperature low-pressure refrigerant in evaporimeter 4.From the cold-producing medium that evaporimeter 4 has flowed out, in inner heat exchanger 5, heated and become gas (F), attracted to compressor 1, form freeze cycle.

Here, expansion valve 3 is so that the suction degree of superheat of compressor 1 becomes the mode of desired value (for example 5～10 ℃) is controlled.Specifically; The temperature slippage of coming the pressure loss in modifying factor evaporimeter 4 and the inner heat exchanger 5 to cause according to the detected value of the 5th temperature detecting unit 32 of the inlet refrigerant temperature that detects evaporimeter 4; Calculate evaporating temperature (ET), use the detected value (Ts) of the 6th temperature detecting unit 33 of the inlet temperature that detects compressor 1 to suck degree of superheat SHs by computes.

SHs＝Ts-ET

According to following formula, so that SHs becomes the aperture that the mode of desired value is controlled expansion valve 3.And; Though represented to calculate the example of evaporating temperature (ET) according to the detected value of the 5th temperature detecting unit 32; But be not limited thereto; Also can export to pressure sensing cell (second pressure sensing cell) 51 (with reference to Fig. 1) are set between the suction inlet of compressor 1, obtain the cold-producing medium saturation temperature from its detected value in the low-pressure side of heat exchanger 5 internally.In addition, the function of returning from the liquid of guaranteeing the viewpoint of equipment dependability, make to prevent compressor 1 has precedence over turn round the well function of water heat exchanger 2 of efficient, so, have precedence over other high efficiency running control and suck degree of superheat control.

In Fig. 2, dot the action on the P-h line chart of occasion of the aperture that has reduced expansion valve 3.In the occasion of the aperture that reduces expansion valve 3, the refrigerant flow that flow into evaporimeter 4 from expansion valve 3 reduces, and the suction degree of superheat of compressor 1 increases temporarily.In addition, cold-producing medium moves towards the high-pressure side, so on high-tension side pressure rises, discharge temperature uprises.Accompany therewith, the water heat exchanger outlet temperature descends, so that the temperature difference in the water heat exchanger 2 becomes necessarily.If the water heat exchanger outlet temperature descends, then the heat exchange amount in the inner heat exchanger 5 descends, the result, and the suction degree of superheat is identical substantially with the aperture that reduces expansion valve 3 state before, shows as certain value.That is, the variation that the aperture of expansion valve 3 changes by the heat exchange amount of inner heat exchanger 5 absorbs (heat exchange amount changes corresponding to the aperture of expansion valve 3), makes the variation that sucks the degree of superheat less.Therefore, only can not guarantee the heating efficiency of water heat exchanger 2, decrease in efficiency through the suction degree of superheat of control compressor 1.Therefore, need be the new control of purpose to guarantee heating efficiency and to improve running efficiency.

Below, according to the reason of the explanation of the Temperature Distribution in the water heat exchanger shown in Figure 3 in generation maximum aspect the performance (COP).

Fig. 3 is the figure of the Temperature Distribution of cold-producing medium in the expression water heat exchanger 2 and water; In the drawings; Thick solid line is represented cold-producing medium; Thin solid line is represented the variations in temperature of water, and Δ T1 representes the temperature difference of water heat exchanger inlet temperature and water outlet temperature, and Δ T2 representes the temperature difference of water heat exchanger outlet temperature and water inlet temperature; Δ Tp representes that cold-producing medium and the temperature difference of water in the water heat exchanger 2 becomes the temperature difference of the narrow point of minimum, and Δ T representes the temperature difference of water heat exchanger inlet temperature and water heat exchanger outlet temperature.As Fig. 4 with respect to such shown in the recurrent state of expansion valve opening; If reduce expansion valve 3 aperture, discharge temperature is risen; Then the heating efficiency at water heat exchanger 2 is that the outlet temperature of water heat exchanger 2 descends under the certain condition of cardinal principle, with the cold-producing medium in the maintenance water heat exchanger 2 and the mean temperature difference of water; In addition, the temperature difference Tp of narrow point also reduces.In addition, because refrigerant amount moves towards the high-pressure side, so discharge pressure rises, input increases, and COP descends.On the contrary; If increase expansion valve 3 aperture, discharge temperature is descended, then the outlet temperature of water heat exchanger 2 uprises, to keep cold-producing medium and the mean temperature difference of water in the water heat exchanger 2; In addition; The temperature difference Tp of narrow point also increases, but owing to the heating efficiency ratio diminishes, so also descend at this occasion COP.Therefore, as dotting among the figure, there is the suitable expansion valve opening that makes COP maximum.

The variation of the operation values that the temperature of the each several part of the occasion that Fig. 5 representes to have changed from the aperture of expansion valve 3 is obtained.Fig. 5 representes the aperture (%) of expansion valve 3 with transverse axis, and the temperature difference T2, heating efficiency that representes the suction degree of superheat, discharge temperature, water heat exchanger outlet temperature of compressor 1 and water inlet temperature with the longitudinal axis is than, COP ratio.Heating efficiency when COP representes by following ratio than all, and said ratio is to establish with respect to expansion valve opening to become the ratio that great value is 100% occasion.Can find out that with respect to the aperture variation of expansion valve 3, the variation that sucks the degree of superheat can be regarded certain value substantially as, is no judge of the variation of heating efficiency ratio, COP ratio by the suction degree of superheat.Can find out; Like the existing occasion that will COP be controlled to be maximum routine according to the poor Δ T2 of discharge temperature, water heat exchanger outlet temperature and water inlet temperature; Near COP as dotting among the figure becomes maximum expansion valve opening; The variation of discharge temperature, temperature difference T2 is little, for COP is controlled to be maximum, needs high-precision temperature survey.

The variation of another operation values that the temperature of the each several part of the occasion that Fig. 6 representes to have changed from the aperture of expansion valve 3 is obtained.Fig. 6 representes the aperture (%) of expansion valve 3 with transverse axis, and the total temperature difference ∑ Δ T of the gateway temperature difference Thx, discharge temperature (water heat exchanger outlet temperature) that representes inner heat exchanger with the longitudinal axis and the poor Δ T of water heat exchanger outlet temperature, above-mentioned Δ T1 and Δ T2, heating efficiency are than, COP ratio.The characteristic of Fig. 6 is represented; Through control the heat exchange amount of inner heat exchanger 5 according to the temperature difference Thx of inner heat exchanger gateway; Or through heat exchange amount according to the total temperature difference ∑ Δ T of Δ T1 and Δ T2 control water heat exchanger 2, can COP become maximum near running.In addition, can learn, the temperature difference T of discharge temperature and water heat exchanger outlet temperature COP become maximum expansion valve opening near also change significantly, if control, then can get peaked Deviation Control less from COP according to temperature difference T., only represent the occasion of temperature difference T here, even but control according to poor (the Δ T1-Δ T2) of temperature difference T1 and temperature difference T2, also can bring into play same effect.

Like this; As the normal condition of water heat exchanger 2, adopt the high-pressure side outlet temperature of inner heat exchanger 5 in the occasion of Δ Thx, adopt discharge temperature in the occasion of Δ T; Occasion at ∑ Δ T adopts discharge temperature and water side gateway temperature, thereby can near the maximum running of implementation efficiency.

In addition; Can learn that from Fig. 6 the total temperature difference ∑ Δ T of the temperature difference T2 of the temperature difference T1 of water heat exchanger inlet temperature and water outlet temperature and water heat exchanger outlet temperature and water inlet temperature becomes minimum, controls the meaning that also has the physics aspect according to this index; Be rational; But T compares with temperature difference, and near the variations in temperature that becomes maximum at COP is little, needs high-precision temperature detection.In addition, can think that become maximum occasion at COP, the temperature difference Tp of narrow point and water heat exchanger outlet temperature equate with the temperature difference T2 of water inlet temperature substantially according to Fig. 3.This is because consider that from the characteristic of heat exchanger 2 temperature difference that in water heat exchanger 2, become minimum do not squint and equal occasion to arbitrary side, can bring into play maximum performance.Therefore, also can make Δ Tp and Δ T2 equally control expansion valve 3.

Below, through so that suck the control action of freezing cycle device that mode that the degree of superheat and above-mentioned temperature difference T converge desired value is controlled example shows Fig. 1 of expansion valve opening.

Fig. 7 is the flow chart of the control action of expression freezing cycle device.In the present invention, from making the preferential purpose of product reliability, make the control ratio of the suction degree of superheat (SHs) of compressor 1 be used to guarantee that the control of temperature difference T of heating efficiency is preferential.

At first, the degree of superheat (SHs) is littler of the occasion (S101) below the predefined convergence range Δ SH than desired value (SHm) sucking, and expansion valve opening is descended, up to sucking the degree of superheat (SHs) convergence.If guarantee to suck the degree of superheat (SHs) like this, then next make temperature difference T converge to desired value.Specifically, littler of the occasion (S102) below the predefined convergence range δ T at temperature difference T than desired value (Δ Tm), expansion valve opening is descended, make temperature difference T convergence.Like this, the lower limit of the suction degree of superheat (SHs) and temperature difference T is suppressed.

Next, arrive the occasion (S103) more than the predefined convergence range Δ SH greatly than desired value (SHm), expansion valve opening is increased, up to sucking the degree of superheat (SHs) convergence in the suction degree of superheat (SHs).Like this, if suck the degree of superheat (SHs) convergence, then next make temperature difference T converge to desired value.Specifically, arrive the occasion (S104) more than the predefined convergence range δ T greatly than desired value (Δ Tm), expansion valve opening is increased, make temperature difference T convergence at temperature difference T.Like this, the higher limit of the suction degree of superheat (SHs) and temperature difference T is suppressed.And, suck the example of the degree of superheat though represented preferential control, use the occasion of compressor to be not limited thereto with endurance of returning with respect to liquid, change priority and also can give play to same effect.Through above control, make the suction degree of superheat (SHs) and temperature difference T converge to desired value.

In above-mentioned explanation; Explained with the mode that converges to desired value (SHm, Δ Tm) and controlled the example that sucks the degree of superheat (SHs) and temperature difference T; But also can use poor (Δ T1-Δ T2) or the Δ Thx of total temperature difference ∑ Δ T, Δ T1 and the Δ T2 of Δ T1 and Δ T2 to replace temperature difference T, so that its mode that converges to desired value is controlled.In the occasion of using ∑ T and (Δ T1-Δ T2), obtain these values according to the detected temperatures computing of first temperature detecting unit 30, second temperature detecting unit 31, the 3rd temperature detecting unit 41 and the 4th temperature detecting unit 42.In addition; In the occasion of using Δ Thx; The high-pressure side of heat exchanger 5 exports between the inlet of expansion valve 3 inner heat exchanger outlet temperature detecting unit 52 (with reference to Fig. 1) is installed internally; According to the detected temperatures of second temperature detecting unit 31 and the detected temperatures of inner heat exchanger outlet temperature detecting unit 52, obtain their temperature difference Thx.

Can learn according to above explanation; In this embodiment; Except the degree of superheat control that compressor sucks, also,, COP controls expansion valve opening so that becoming the mode of maximum according to the temperature difference T of discharge temperature and water heat exchanger outlet temperature (or ∑ Δ T, Δ T1-Δ T2, Δ Thx); So, can obtain high efficiency freezing cycle device.

In addition, according to the output of the 5th temperature detecting unit 32 or pressure sensing cell 51, obtain cold-producing medium saturation temperature (ET); Then, obtain the suction degree of superheat (SHs) through the detected temperatures (Ts) and the cold-producing medium saturation temperature (ET) of the 6th temperature detecting unit 33, so that the mode that this suction degree of superheat (SHs) becomes desired value is controlled expansion valve opening; So; Can guarantee the degree of superheat of the suction portion of compressor 1, can prevent that liquid from returning to compressor 1, can guarantee reliability.In addition, the example that in the example of Fig. 1, the 5th temperature detecting unit 32 is located between expansion valve 3 and the evaporimeter 4 is illustrated, but so long as the inlet of the low-pressure side from the inlet of evaporimeter 4 to inner heat exchanger 5, then also configurable in any position.

In addition, in this embodiment, when the control degree of superheat and the above-mentioned temperature difference (Δ T, ∑ Δ T, Δ T1-Δ T2, Δ Thx), carry out the control of the degree of superheat, also guaranteed the reliability of compressor 1 from this point with the mode of the control that has precedence over the above-mentioned temperature difference.

In addition, in this embodiment, radiator is made up of water heat exchanger, can obtain high efficiency hot water supply device.

Embodiment 2

Below, the freezing cycle device of embodiment of the present invention 2 is described.

Fig. 8 is the figure of the formation of expression freezing cycle device of the present invention.Be with embodiment 1 different point, first temperature detecting unit 30 that first pressure sensing cell 35 replaces the discharge temperature of detection compressor 1 is set.Obtain the imaginary saturation temperature (below, be called imaginary saturation temperature) of the normal condition that becomes water heat exchanger 2 according to this first pressure sensing cell 35.In addition, this first pressure sensing cell 35 for example can be shared with the pressure sensor that is provided with for the abnormal ascending that prevents high pressure.The running action is identical with embodiment 1, so, omit explanation.

In this embodiment, same with HFC series coolant in the past, calculate the imaginary supercooling degree of water heat exchanger 2 outlets, the refrigerant condition of control water heat exchanger 2 outlets.Specifically; First pressure sensing cell 35 that is provided with from substituting first temperature detecting unit 30; Obtain the normal condition of imaginary saturation temperature as water heat exchanger 2; From imaginary saturation temperature Tsat poor with by the outlet temperature Tcout of second temperature detecting unit, 31 detected water heat exchangers 2, obtain imaginary supercooling degree (below, be called imaginary supercooling degree SC) by following formula.

SC＝Tsat-Tcout

In this embodiment, likewise control the aperture of expansion valve 3 with the occasion of the flow chart of Fig. 7, so that the SC that has been obtained by the aforementioned calculation formula becomes the maximum desired value (SCm) of efficient.

The method of obtaining of imaginary saturation temperature here, is described.

Fig. 9 and Fig. 2 are same, are the figure of the running action of expression freezing cycle device of the present invention on the P-h line chart.As imaginary saturation temperature,, then can freely set if make the such definition clear-cuts such as vertical line of enthalpy of pseudocritical temperature track, the dotted line イ of the such isothermal flex point of connection of dotted line ア for necessarily prolonging by critical point.But, by maximal efficiency running freezing cycle device, as having explained before this, should select near the temperature difference of maximal efficiency and become big such imaginary saturation temperature for stably.At this moment; The imagination saturation temperature is promptly put the isobaric line of force and the intersection point of dotted line ア at the pressure place of B as the detected value of first pressure sensing cell 35, or the isobaric line of force and the intersection point of dotted line イ of promptly putting the pressure place of B as the detected value of first pressure sensing cell 35 are obtained.

In this embodiment, use imaginary saturation temperature to replace the discharge temperature of compressor 1, so, can omit first temperature detecting unit 30 of Fig. 1, can realize cost degradation.In addition, same with HFC series coolant in the past, the supercooling degree of control water heat exchanger 2 outlets, so, the control that can directly use the expansion valve that in the past used.

Claims

1. freezing cycle device; At least comprise decompressing unit, heat dump, inner heat exchanger that compressor, radiator, aperture can change, this inner heat exchanger makes the cold-producing medium of export department of cold-producing medium and above-mentioned heat dump of the export department of above-mentioned radiator carry out heat exchange; It is characterized in that:

Have detection from first temperature detecting unit of the refrigerant temperature between the inlet that exports to above-mentioned radiator of above-mentioned compressor, detect second temperature detecting unit from the refrigerant temperature between the high-pressure side inlet that exports to above-mentioned inner heat exchanger of above-mentioned radiator, detect the inlet temperature of heated medium the 3rd temperature detecting unit, detect the 4th temperature detecting unit of the outlet temperature of heated medium

So that the mode that becomes desired value with (∑ Δ T) of the temperature difference (Δ T2) of the temperature difference of the detected temperatures of the detected temperatures of above-mentioned first temperature detecting unit and above-mentioned the 4th temperature detecting unit (Δ T1) and above-mentioned second temperature detecting unit and above-mentioned the 3rd temperature detecting unit is controlled the aperture of above-mentioned decompressing unit.

2. freezing cycle device according to claim 1 is characterized in that: have detection exports to the refrigerant temperature between the suction inlet of above-mentioned compressor from the low-pressure side of above-mentioned inner heat exchanger the 6th temperature detecting unit,

Have precedence over the aperture control of the decompressing unit of utilizing the above-mentioned temperature difference; Calculate the degree of superheat of compressor suction portion according to the detected temperatures of the cold-producing medium saturation temperature at the detection position of above-mentioned the 6th temperature detecting unit and above-mentioned the 6th temperature detecting unit, so that the above-mentioned degree of superheat becomes the aperture that the mode of desired value is controlled above-mentioned decompressing unit.

3. freezing cycle device according to claim 2; It is characterized in that: export in low-pressure side between the suction inlet of above-mentioned compressor second pressure sensing cell is set, obtain above-mentioned cold-producing medium saturation temperature according to the detected value of above-mentioned second pressure sensing cell from above-mentioned inner heat exchanger.

4. freezing cycle device according to claim 2; It is characterized in that: the inlet from above-mentioned heat dump is provided with the 5th temperature detecting unit to the low-pressure side inlet of above-mentioned inner heat exchanger, obtain above-mentioned cold-producing medium saturation temperature according to the detected temperatures of above-mentioned the 5th temperature detecting unit.

5. freezing cycle device according to claim 1 is characterized in that: above-mentioned radiator is the heat exchanger that carries out heat exchange with water.

6. freezing cycle device according to claim 1 is characterized in that: use carbon dioxide as cold-producing medium.